Wine is an alcoholic beverage made from the fermentation of grape juice. It is produced by fermenting crushed grapes using various types of yeast which consume the sugars found in the grapes and convert them into alcohol. Various varieties of grapes and strains of yeasts are used depending on the types of wine produced.
A good way of ensuring that you always have red or white wine spare for cooking is to freeze any left-overs in small platic coffee cups. They can be defrosted in a microwave and used immediately.